Pharmacokinetics and hepatic first-pass effect of (-)-carbovir in the anesthetized rat.

Studies were designed to allow an in vivo estimation of the hepatic extraction ratio and to test the hypothesis that the pharmacokinetic parameters of (-)-CBV are significantly different during anesthesia. (-)-CBV was administered as an i.v. bolus followed by i.v. infusion into either the portal (n = 3) or the jugular (n = 3) veins of anesthetized male Sprague-Dawley rats. These studies indicate that (-)-CBV had a very low hepatic extraction ratio, in agreement with previous (-)-CBV in situ liver perfusion studies. Additionally, anesthesia was shown to alter the pharmacokinetics of (-)-CBV by reducing the total body clearance of this drug.